Walk the path around the Brookline Reservoir on a January morning and the water sits flat and steel-colored while Route 9 wakes up behind the trees. G&G LANDSCAPING SERVICES LLC is already out by then, plowing driveways and opening walks toward the Chestnut Hill end of town, laying salt before the afternoon melt refreezes into something worse. Come April the trucks trade blades for mowers and the year turns into cutting, mulching, and keeping the leaves from swallowing a lawn each autumn. Two seasons, one habit: arrive before the mess does. A driveway cleared by seven in the morning is a small promise kept.